Screw clamp



Dec. 31, 1929. J. IDOHNAL 1,741,923

SCREW CLAMP Filed March 14, 1929 Patented Dec. 31, 1929 UNIT stares JAN IDOHNAL, F DOZBRIS, CZECHOSLOVAKIA SCREW CLAMP Application filed March 14, 1929, Serial No.

The invention relates to a screw clamp in which the arm that constitutes the bearing for the clamping screw is arranged as a lever, to which an adjustable forked arm, that is provided on the longer branch of the angle rail, is connected by means of a pivot on j which the lever with the clamping screw can rotate, the free, upper end of the lever being provided with teeth which prevent the forked arm from slipping on the angle rail when objects are clamped in the device. As it is necessary for certain classes of work to have the screw clamp standing in a vertical position the invention provides for a pin which is passed through the shorter branch of the angle rail and bent downwards on both ends so as to form a foot on which the screw clamp rests when standing in a vertical position.

In the accompanying drawing the invention is illustrated in one form by way of example in which Figure 1 is a side elevation of the screw clamp, Figure 2 a plan view of the same, Figure 3 is a front elevation of the forked and lever arms alone showing the connection between these two parts, and Figure 4 a screw clamp on a smaller scale standing up in a vertical position.

The forked arm 6 is guided on the longer branch of the angle rail a and connected with the lever c by means of the pivot (Z in such a manner that the lever can be rotated. The clamping screw 0 with the handle f on one end and a clamping jaw g on the other end is arranged in the lower end of the lever c in the usual manner. The clamping plate It is provided on the shorter branch of the angle rail a oppositethe clamping jaw g.

When any object is to be clamped between the clamping plate and the clamping in the screw clamp, the lever c rotates in the direction indicated by the arrow :0 on the pivot d until the clamping action is attained by means of turning the clampingscrew the lever c then takes up the pressure generated and transfers it, by rotating in the direction indicated by the arrow 3 as a counter pressure by means of the teeth on its upper end onto the rail a, so that the lever becomes firmly positioned and the forked arm cannot slip on the angle rail.

347,120. and. in Germany January 31, 1928.

The pin 2' which is firmly located in the shorter branch of the angle rail, is bent clownward on both ends so as to form a foot upon which the screw clamp may stand in the position as shown in Figure 4. The single parts of the device are to be preferably made of hardened steel, which is particularly advantageous for the surfaces between the lever c and the angle rail against premature wearing away of the material.

I claim:

1. A screw clamp, comprising, in combination, a lever arm connected so as to be rotatable, with an adjustable forked arm provided on the longer branch of the angle rail of a screw clamp, the free, upper end of the said lever being provided with teeth adapted to engage against the inner surface of said longer angle rail branch and to hold said adjustable forked arm firmly located in any r given position on said rail branch, said lever arm being provided with a clamping screw having a handle and a clamping jaw and means for holding said screw clamp standing in a vertical position, substantially as set forth.

2. A screw clamp, comprising, in combination, a lever arm connected, so as to be rotat able, with an adjustable forked arm provided on the longer branch of the angle rail of a screw clamp, the free, upper end of said lever being provided with teeth adapted to engage against the inner surface of said longer angle rail branch and to hold said adjustable forked arm firmly located in any given position on the said rail branch, said lever arm being provided with a clamping screw having a handle and a clamping jaw, a pin through the shorter branch of said angle rail, said pin being bent down on both ends to form a foot adapted to hold said screw clamp standing in a vertical position, substantially as described.

J AN DOHNAL. 

